Artist impression of the interior of Jupiter

What is Jupiter Made Of?

22 May , 2008 by

Of all the Jovian related questions that we get here at Universe Today, what is Jupiter made of is one of the most common. Jupiter is mainly composed of hydrogen and helium just like a star. Answering that question seems to open a flood of other questions about the gas giant, so here are some facts about Jupiter that should answer quite a few of them.

Jupiter does not have enough mass to ignite fusion and become a star like our Sun. Without that mass, Jupiter is also too cold for fusion. If Jupiter were to become 80 times more massive it would be able to generate enough heat for fusion through gravitational compression. Given that there isn’t that much mass in our Solar System, outside of the Sun, it is impossible for Jupiter to become a star. Can you imagine how scorched and barren all of the planets would be if ours was a binary star system?

Spectral analysis of Jupiter has revealed that in addition to hydrogen and helium, the planet is made of water, methane and ammonia. Those elements are in trace amounts. The core of the planet is thought to contain some rock and metallic hydrogen. Scientists estimate that the core is heated to 36,000 K. The planet is not just a ball of gas that you would be able to drop straight through. In addition to the rocky/molten metallic hydrogen core, there is a layer of liquid hydrogen and helium and areas where the hydrogen is in a supercritical state, meaning that it does not have distinct gas and liquid phases.

Another frequent question about Jupiter is about the ”stripes” that can be seen. Those stripes are actually an effect of the fast rotation of the planet. To be more specific, they are due to the combination of the planet’s rotation and that its gases are more intensely heated at the equator than the poles. This is similar to why the Earth has trade winds near the equator and jet streams near the poles…rising air interacts with the coriolis effect of the rotation and causes sideways deflections. Jupiter rotates much faster and has a thicker atmosphere, so its coriolis effect is much stronger, thus the stripes. Try this link for a more in depth explanation of the striations(stripes).

Just asking what is Jupiter made of only brings up a whole other set of questions. Be sure to keep looking and you will find plenty to stump your friends and teachers with.

We have written many articles about Jupiter for Universe Today. Here’s an article about the color of Jupiter, and here’s an article about the missions to Jupiter.

If you’d like more information on Jupiter, check out Hubblesite’s News Releases about Jupiter, and here’s a link to NASA’s Solar System Exploration Guide to Jupiter.

We’ve also recorded an episode of Astronomy Cast just about Jupiter. Listen here, Episode 56: Jupiter.


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Kemp Woods
Kemp Woods
December 8, 2008 12:49 AM
For what it’s worth I’ll quickly say that I believe that Jupiter has a mega ocean of liquid water , the surface of which lies about 180 miles below the visible cloud tops. I base this upon the results of the Galileo probe, the Shoemaker-Levy Comet impact observations, and my research into the equations of state– as poorly known as they are. After years of gas giant baloney it doesn’t surprise me that they now talk about ice on top of a rocky core. My main point is that if any planet has liquid water oceans it is surely Jupiter (and Saturn for that matter). I am quite sure that Jupiter is rife with life. Even without oceans!… Read more »